Ultraviolet (UV) light irradiation provides disinfection through the transference of electromagnetic energy at a germicidal wavelength that is absorbed by a microorganism's genetic material.  UV light lies on the electromagnetic spectrum above the frequency to be categorized as X-rays but below that required for visible light. The UV wavelengths have the ability to damage cells of microscopic organisms by structurally altering the DNA molecule or RNA in viruses.  The damage can kill the cell or prevent proper reproduction. 

There are several advantages for using UV disinfection to inactivate most viruses, spores and cysts.  A low dose of ultraviolet light can kill 99.99 percent of the fecal coliform and fecal streptococcus.  UV disfection is a physical process rather than a chemical; thus, eliminating the need to generate, handle, transport, or store toxic, hazardous, or corrosive chemicals.  UV disinfection also produces no toxic residuals that could be harmful to humans or aquatic life.